1. Field of the Invention
The present invention relates to recalibration techniques and, in particular, to recalibration techniques for implantable sensors.
2. Description of Related Art
The accuracy of a sensing system is generally limited by the drift characteristics of the sensing element over time and the amount of environmental noise introduced into the output of the sensing element. To accommodate the drift inherent in the sensing element and the noise inherent in the system environment, the sensing system is periodically calibrated, or recalibrated.
A typical recalibration routine is performed at regular intervals. Generally, a technician will measure an output of the sensing system in response to a known, accurate input. The sensing system is then adjusted, or recalibrated, so that the output of the sensing system matches that of the known, accurate input to within an acceptable error margin.
Typical recalibration routines are often inadequate for many sensing systems. Many sensing systems include sensing elements that exhibit non-linear outputs or outputs that change in a non-linear fashion over time. Thus, a simple linear adjustment during a recalibration procedure to force an output of the sensing system back to acceptable output values often fails to account for the true nature of many sensing elements. The result of simple linear adjustments may be a sensing system that is accurate only over a small range of the sensing elements capabilities or a sensing system that may not maintain acceptable levels of accuracy for extended periods of time.